A substance composed of lipoprotein that is secreted by the alveolar cells of the lung and serves to maintain the stability of pulmonary tissue by reducing the surface tension of fluids that coat the lung.

A substance that, when dissolved in water, lowers the surface tension of the water and increases the solubility of organic compounds. Surfactants are used in inks to increase the effects of capillary action; detergents are surfactants that help remove organic compounds from a substance by making them dissolve more readily in the water in which the substance is washed.

A substance composed of lipoprotein that is secreted by the alveolar cells of the lung and maintains the stability of pulmonary tissue by reducing the surface tension of fluids that coat the lung.

surface-active agent

substance such as a detergent that, when added to a liquid, reduces its surface tension, thereby increasing its spreading and wetting properties. In the dyeing of textiles, surface-active agents help the dye penetrate the fabric evenly. They are used to disperse aqueous suspensions of insoluble dyes and perfumes.